New alkali-free boroaluminosilicate glass, for thin film transistor matrix substrates or AMLCD manufacture for liquid crystal displays

摘要

The alkali-free glass has the composition (by wt.): 57.5-60.5 % SiO2, 9-12 % B2O3, 12-16 % Al2O3, 4-6 % CaO, 0-3 % MgO, 4-8.5 % BaO, 0-5 % SrO, 0-3 % ZrO2, 0-0.5 % As2O3 and 0-0.5 % Sb2O3. The glass has a thermal expansion coefficient ( alpha 20-300) of 3.75 !0.4*10-6 K-1, a density of less than 2.55*10-3 kg/m3 and a strain point (14.5) of - 650 deg C. For example, the glass may have the composition (by wt.): 60.3 % SiO2, 10.9 % B2O3, 12.6 % Al2O3, 4.0 % CaO, 1.5 % MgO, 7.6 % BaO, 0.3 % SrO, 2.4 % ZrO2, 0.4 % As2O3 and 0 % Sb2O3. The glass may have a thermal expansion coefficient ( alpha 20-300) of 3.76*10-6 K-1, and a strain point (14.5) of 672 deg C. An Independent claim is included for a method for manufacturing thin glass substrates.